A New Spectrum Sensing Algorithm Research Base On Adaptive Threshold

With the rapid development of wireless communication technology, the demand for wireless spectrum resources is increasing greatly, while the contradiction of the limited spectrum resource and the low spectrum utilization rate is growing. The key and premise to cognize radio is spectrum sensing, which provides a new way for the spectrum efficiency enhancement through the rapid empty space detecting and finding accurately.This dissertation mainly focuses on the cooperative spectrum sensing algorithm based on adaptive threshold. Firstly, the scope of several common single-user spectrum sensing technology is analyzed. For the degradation of spectrum sensing performance caused by hidden terminal, channel fading and shadowing effects, the multi-user collaborative spectrum sensing technology is introduced. The cooperative spectrum sensing technology makes full use of the diversity gain to improve the sensing performance at the expense of increased overhead. On this basis, an alternating upload strategy is proposed considering the effect of energy consumption on the system detection performance. The algorithm ensures the detection performance, meanwhile, It reduces the detection data transfer times, energy consumption and the overhead of the system. The simulation results show the effectiveness of the algorithm.The setting of traditional decision threshold is only related to the false alarm probability, as a result, it cannot adapt to dynamic perception environment of the cognitive users(SNR, etc). Based on this, a double threshold cooperative spectrum sensing algorithm based on adaptive threshold is proposed. The algorithm starts with the decision threshold, dynamically adjusts the decision threshold based on the difference of cognitive users sensing environmental quality to increases the accuracy of spectrum sensing. The theoretical analysis and simulation results show that the algorithm can improve the sensing performance of the system.Finally, a clustering cooperative spectrum sensing algorithm based on adaptive threshold is proposed. The algorithm solves the signal fading caused by the non-ideal control channel between cognitive users and the fusion center and reduces the data transmission between the cognitive nodes and the fusion center and the transmission error rate in the control channel. The algorithm could adapt to the dynamic change of sensing environment, within the cluster using adaptive double threshold instead of "OR" algorithm, which is the further application of the double threshold cooperative spectrum sensing algorithm with adaptive threshold and improves the sensing performance of the whole system. The simulation results prove the validity and feasibility of the algorithm.